Multi-reaction processes for making product mixtures of ethanolamines and ethyleneamines from ethylene oxide and ammonia are known. See, for example, PCT Publication Number WO 2006/114417 and U.S. Pat. No. 4,400,539 (Gibson et al.).
PCT Publication Number WO 2006/114417 discloses a method for producing ethyleneamines, in which ethylene oxide (EO) is continuously reacted with ammonia on an inorganic ion exchanger as a heterogeneous catalyst in anhydrous conditions in a first reaction stage, the obtained reaction product containing monoethanolamine (MEOA), diethanolamine (DEOA), and triethanolamine (TEOA) at a weight ratio MEOA:DEOA:TEOA=80-94:5.9-15:0.1-5, and the reaction product is then continuously reacted with ammonia in the presence of hydrogen and a heterogeneous hydrogenation catalyst in a second reaction stage.
Gibson et al. discloses a continuous process for the manufacture of ethylenediamine from the products of the reaction of ethylene oxide and ammonia, provision of a continuous recycle stream of monoethanolamine to the products of the reaction of ethylene oxide and ammonia, the amination of such products of the reaction of ethylene oxide and ammonia combined with the monoethanolamine recycle in which the feed stream to the amination reaction zone contains at least 70 weight percent monoethanolamine as well as diethanolamine and triethanolamine, the moles of ammonia provided to the amination reaction exceeds the molar concentration of alcoholic hydroxyl groups present in the amination feed, and the feed to the amination reactor contains at least a 5% increase in the concentration of monoethanolamine over the concentration of monoethanolamine in the reaction product stream from the reaction of ethylene oxide and ammonia.
There is an ongoing desire to improve upon such known processes by reducing capital costs, reducing energy costs/improving operating efficiency, improving catalyst selectivity, improving product quality, improving product selectivity, combinations of these, and the like.
For example, it is desirable to manufacture ethanolamines and ethyleneamines from ethylene oxide and ammonia with the minimum amount of unit operations (e.g., ammonia recycle systems, water removal systems, combinations of these, and the like), yet be able to keep impurity levels at a minimum by reducing the production of impurities as by-products and/or being able to remove by-product impurities more effectively.